Lightning strike at night over a city
{"Image ImageDescription": "Lightning. Branching lightning bolt at night over a city. Lightning occurs when a large electrical charge builds up in a cloud; a potential difference of 10,000 volts a centimetre is needed for electrical discharge through air. At first, leaders of electrons descend towards the ground. As soon as one makes contact an enormous return stroke surges up the leader's ionised path, producing blinding white light and temperatures as high as 30,000 degrees Celsius. The other leaders also discharge themselves through the one that made contact with the ground, producing the branching effect seen here. Photographed on a summer night over Tucson in Arizona, USA.", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image YCbCrPositioning": "Centered", "Image Copyright": "Science Photo Library"}